Method and system for simulating the solar cycle

ABSTRACT

A system for simulating the lighting cycle of the sun comprising: means for obtaining a set of inflection points on a solar lighting cycle and obtaining the annual minimum sunlight value for a location at a predetermined latitude; means for reconstructing the daily and yearly solar cycle based about said set of inflection point and said minimum yearly value; means for determining the lighting period based upon said daily and yearly cycles; and means for activating a lighting device for the determined lighting period.

FIELD OF THE INVENTION

The invention relates to devices and methods which simulate the naturalcycle of the sun. Specifically, the invention relates to devices andmethods which reproduce the daily and yearly solar cycle and otherenvironmental conditions.

SUMMARY OF THE INVENTION

It is a principle object of the invention to provide an algorithm thatapproximates the yearly solar cycle.

It is another object of the invention to provide an algorithm forcalculating the amount of daily solar radiation over a year of aparticular location which is adjustable for latitude of the location.

It is still another object of the invention to provide a system thatsenses the moisture level of the soil and is able to provide the propermoisture adjustments for the soil.

It is a further object of the invention to provide a system where theuser can monitor data concerning the soil such as its pH, alkalinevalue, temperature and nutrient condition.

It is another object of the invention to provide an algorithm thatcalculates the solar cycle beginning on the winter solstice.

It is still another object of the invention to provide an algorithmwhich provides five seasonal sections creating the four seasonalchanges.

It is yet another object of the invention to provide an algorithm thatcalculates the solar cycle with the algorithm aligning on the wintersolstice yet allowing the user to initialize the algorithm to start atany point in time along the yearly cycle.

Still another object of the invention is to provide an algorithm whichprovides five seasonal sections creating the four seasonal changes whichallows the algorithm to align on the point of allegorical origin, thewinter solstice.

It is a further object of the invention to provide a system thatincorporates methods of stimulating plant growth.

It is yet another object of the invention to provide a system thatreconstructs the duration and intensity of the daily solar cycle in realtime.

It is still another object of the invention to provide a system that iscompact in size and easy to use.

These and other objects are accomplished in a system for simulating thelighting cycle of the sun comprising means for obtaining a set ofinflection points on a solar lighting cycle and obtaining the annualminimum sunlight value for a location at a predetermined latitude; meansfor reconstructing the daily and yearly solar cycle based about said setof inflection point and said minimum yearly value; means for determiningthe lighting period based upon said daily and yearly cycles; and meansfor activating a lighting device for the determined lighting period.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a block diagram of the system according to principles of thepresent invention;

FIG. 1b is a diagram of the control panel with LEDs according toprinciples of the present invention;

FIG. 1c is a block diagram of the system according to principles of thepresent invention;

FIG. 1d is a block diagram of the system with a fertilizer dispenseraccording to principles of the present invention;

FIG. 1e is a block diagram of a network of systems according toprinciples of the present invention;

FIG. 1f is a circuit diagram of the lamp power supply according toprinciples of the present invention;

FIG. 1g is a block diagram of another embodiment of the system accordingto principles of the present invention;

FIGS. 2a-2b are flowcharts of the operation of the system according toprinciples of the present invention;

FIG. 3 is a graph of the intensity of solar radiation over a given yearaccording to principles of the present invention; and

FIGS. 4a-4c are flowcharts of the lighting time determination algorithmaccording to principles of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1a, lamps 1 emit light onto plants 2. The amount,intensity, and duration of the light is determined by the algorithmdescribed in detail, below. To provide proper moisture levels for theplants 2, a water pump 3a pumps water to the plants 2 from an outsidewater line. A water sensor 3b determines the moisture level of the soilcontaining the plants 2 and heating elements 3c warm the soil where theplants 2 are placed. To stimulate the thermal conditions of the soil, asoil vibrator 3d moves the soil. A controller 4a activates a water pump3a, soil heater 3c, soil vibrator 3d, and receives soil-moisture datafrom a water sensor 3b. A control panel 4b coupled to the controller 4aallows a user to enter commands directing the operation of the system. Ahost computer 4c is also connected to the controller 4a allowing theuser to enter commands; such commands may include instructions toperform a measurement or display results of previous measurements. Thehost computer 4c also displays and analyzes data from the system such astemperature and soil moisture levels. Although the description aboverelates to systems involving plants, it will be understood that theprinciples of the invention can be applied to any environment requiringan accurate reproduction of the daily and yearly solar cycle.

Referring now to FIG. 1b, the control panel contains a button 7aallowing the user to activate and control the system. A "season code"LED 7b is lit by controller 4a and indicates the current season"section" or the current season by flashing a predetermined number oftimes. For example, LED 7b may flash once for spring and twice forsummer to indicate the system is in that particular season. A "bulb out"LED 7c flashes if the lamp gives no light. A "pump indicator" LED 7d islit by controller 4a if the water pump is operating and turned offotherwise. A "low moisture level" LED 7e is activated until a requestedwater level is achieved by the system. The personal computer 4c can beequipped with software as is known in the art to display the aboveinformation. LEDs 7f, 7g, 7h indicate a low soil pH, a low alkalinelevel, and the state of the heater.

Referring now to FIG. 1c, an alternate embodiment of the system is nowdescribed. A central processing unit (CPU) 178 is supplied with powerand is clocked by a crystal clock 176. The central processing unit 178is preferably a PIC12C5 series microcontroller manufactured by MicrochipTechnology, Inc. although any other comparable microcontroller can beused. A season switch 186 is coupled to the CPU 178 and indicates theproper season to the CPU 178. The CPU 178 communicates through a controlinterface 162 which comprises an analog-to-digital converter 163 and bus165. The analog-to-digital converter 163 changes analog signalsrepresenting humidity and ambient temperature to digital signals andthen transmits the digital signals over the bus 165 to the CPU 178. Theanalog-to-digital converter 163 is a LM331 analog-to-digital converteror any similar device.

The CPU 178 also sends signals over the bus 165 to season LED 154 whichindicates the season to the user and water LED 164 which indicates lowmoisture level of the plant. Additionally, the CPU 178 transmits signalswhich activate a temperature control 172 (which controls the heater188), a vibrational transducer 174, a water pump 190, and a lamp powersupply 152.

The lamp power supply 152 receives power and provides for the properturn on times of lamps 150. The lamp interface turns on the lamp 150which supplies light to plants 158 which are bedded in soil alkaline170. The plants 158 are housed in a planter 168 with a base 180. Theinterface 162 receives information concerning the intensity of the lightof the lamps 150 by the intensity sensor 154 and moisture informationfrom the moisture sensor 166. The interface 162 also controlstemperature control 172. The temperature control 172 activates a heater188 which warms the soil and a vibrational transducer 174 which agitatesthe soil as needed. Reservoir 184 provides water to the water pump 190which provides water to the plants via pipe 160.

Yet another embodiment of the system is illustrated in FIG. 1d. For thepurpose of mixing fertilizer 216 and water from an outside water line, aCPU 26 sends signals which open and close a valve 214. The fertilizerwater mixture at the output of valve 210 is subsequently stored infertilizer tank 210. A pump 218 applies the fertilizer-water mixturefrom the fertilizer tank 210 to the plants 202. The CPU 206 alsocontrols lamps 200 which supply light to the plants 202. Additionally,the CPU activates a water pump 204 which applies water from a water tank208 to the plants 202.

Referring now to FIG. 1e, a network of systems which simulate the dailyand yearly solar cycles comprises a first lighting system 256, a secondlighting system 258 and a third lighting system 260. These systems areof the types described in connected with FIGS. 1a, 1c, and 1d anddescribed above. The systems 256, 258, and 260 communicate with a hostCPU 250 which sends alarms over a communication channel 251 to a modem252. The alarms are messages which indicate low water level or faultyequipment, for example. The modem is coupled over telephone lines 251 toa remote computer 254 which has software which monitors the systems 256,258, and 260 as well as the host CPU 250.

Referring now to FIG. 1f, the lamp power supply of the present inventionis illustrated. A transistor Q1 is activated on by a signal over signalline S1 from the CPU. Resistors R3 and R4 bias the transistor Q1 andtransistor Q1 biases a transistor Q2. When activated by Q1, Q2 begins toconduct section 2 of the transformer T1. The conduction of this sectionof the transformer T1 induces a voltage in transistor section 3 furtherdriving the transistor Q2 toward saturation. When saturation of Q2occurs, the voltage inducement halts. The magnetic field createdcollapses, which induces a voltage in section 1 of the transformer. Thevoltage in this section of the transformer is passed through D2 and isapplied to the lamp L1. As the collector of Q2 is biased, this induces avoltage through C2 into the filament of the lamp L1 causing the heatingof that filament. When the filament is sufficiently heated, the lampproduces light. The power from section 1 of the transformer lights thelamp L1. Capacitors C3 and C5 act as filters for switching spikesproduced by the transistor Q1. R5, R7 and C1 control the operating pointof Q2.

Referring now to FIG. 1g, a florescent lamp 192 sends light to reflector193 to the outer areas of a plants 158. The florescent lamp 192transmits light in the high frequency range of the visible spectrum. Inorder to transmit light in the low frequency range of the visiblespectrum, an incandescent bulb 194 is used. The bulb is activated by abulb drive signal which is driven by the CPU. The reflector 193 isadjustable so that the light incident on it can shine on the outer areasof the plant. To this effect, the reflector has sides which are hingedto the top of the reflector body. The other elements of the system arethe same as those as described above in reference to FIG. 1c, andfunction in a similar manner.

Referring now to FIGS. 2a and 2b, at step 10 startup of the systembegins. Next, at step 12, the variables used in calculations arecleared, the lamps are turned off, and the water pump is turned off.Variables cleared include those associated with the "lighting time"algorithm which is described below. At step 14, the system determineswhether the control button has been pressed. If the answer is negative,then the system returns to step 14 and determines whether the button 7ahas been pressed.

If the answer to step 14 is affirmative, then the system sets thevariable "season" to the correct season and activates the plant lamp.The "correct" season is determined by where in what part of the growthcycle the plant is in. For example, the plant may be in full bloom,indicating that it is in the "summer" part of the growth cycle.Alternatively, the variable season could be set to the current season.At step 18, the system determines if the control button has beenpressed. If the answer to step 18 is negative, the system continues withstep 22 as described below. If the answer to step 18 is affirmative,then at step 20 the system increments the season entry to the nextseason. For example, if the season is currently "spring", it will beincremented to "summer" or if the season is currently "winter" then theseason will be incremented to "spring."

At step 22, the season code LED is flashed by the system indicating theseason in the cycle where the light is being simulated. Next, at step 24the "bulb out" detector sounds an alarm if the lamp gives no light. Thealarm may be an audio alarm or display a message on the screen of hostcomputer 4c. At step 26, the system determines if the soil needs water.This is accomplished by receiving data from the sensor 3b. If the answerto step 26 is affirmative, the system continues with step 28, asdescribed below. If the answer to step 26 is negative, then at step 30,the water pump is turned on and, at step 32, a LED indicates a low waterlevel. The system then continues with step 34.

At step 28, the system turns off the "pump off" LED indicating that thewater pump is off and that no water is needed by the plant. The systemthen continues with step 34. At step 34, the system determines whetherthe daylight cycle has been completed. If the answer is negative, thesystem continues with step 42 as described below. If the answer to step34 is affirmative, then the system continues with step 36 where the lampis turned off. Next, at step 38, the soil heating is relaxed based onseasonal temperatures under computer control. Then, at step 40 a new daycycle time is calculated based on the algorithm described below. Thesystem returns to step 18 where control proceeds as described above.

At step 42, the system adjusts the intensity of the lamps as the dayprogresses which simulates the angle of the sun. For example, the lampintensity is adjusted to be greatest in the middle of the day and leastat the beginning and end of the day. The soil heating is controlled atstep 46 as the day progresses in a manner similar to that regarding lampintensity. Next, at step 48, the soil is vibrated periodically tosimulate the soil's thermal condition and simulate root growth. Thesystem then returns to step 18 where control proceeds as describedabove.

The cyclical physical stimulations used at step 48 are in the form oflow frequency vibrations induced into the soil on command by a specificfunction contained with the above-described algorithm. This stimulationhas the effect of recreating the thermal expansion and contraction ofthe soil as well as wind movement that would otherwise be present in anoutdoor environment. Both wind movement and thermal expansion affect thestrength of the plants. A plant sitting in an indoor environment lacksthe vital thermal stimulation or subtle movement of surrounding soil. Acomputer can be programmed for various stimuli based on the naturalclimate of a given plant. In addition to physical stimuli, a thermalstimulus is applied to the soil (controlled heating of soil) at step 46.

The algorithm used to calculate the duration of daily light is nowdescribed in greater detail in FIGS. 3 and. 4a-4c. As shown in FIG. 3,the number of minutes of daylight can be approximated by a sinusoidalcurve 90. As will be described below, the algorithm estimates thesinusoidal curve by a piece-wise, linear approximation. The shape ofthis approximation curve is affected by the latitude of the location ofthe system. For example, as shown in FIG. 3, curves for Chicago andMiami will vary due to the different latitudes of these two cities. Itwill also be noted in reference to FIG. 3 that the year is dividedamongst five sections which are used to simulate the traditional fourseasons; these five seasons include pre-spring, spring, summer, winter,and fall.

The algorithm of FIGS. 4a-4c reconstructs the sinusoidal cycle at thepoints of maximum and minimum inflection of the curve which occur wherethe second derivative of the sinusoidal curve is the highest and wherethe first derivative at a point becomes zero. Where the secondderivative of the curve is the lowest, the first derivative reaches itshighest place (i.e., the lighting curve has its greatest rate ofchange). From the reconstruction, the algorithm determines the durationof light from the lamps for a particular date.

As described below, the invention allows the cyclic reconstruction tobegin on the winter solstice, December 21, and proceeds with fiveseasonal sections instead of the traditional four seasons. Of course,the reconstruction could begin upon any date. This feature allowsalignment on the winter solstice. Subsequent seasonal settings, ifdesired, can be accomplished by advancing the seasonal start point.Thus, the algorithm reconstructs both daily and yearly sunlightvariances automatically and without intervention throughout 365 days.

As described below, a set of seven integer numbers along with a specialnumber that sets a minimum value are determined in order to reconstructthe sun's daily and yearly cycles. These values include the points thatmark the five seasons and the upward and downward slopes during springand fall. The set of values determined at this step allows the system tolinearly generate the first and second derivatives for the sinusoidallighting curve, which are used then used to determine a lighting timefor a particular day. This method has the advantage of minimizing theerror of lighting between 2 to 4% over the course of a year.

Referring again to FIGS. 4a-4c, the algorithm which determines theduration of daily light includes entry points into the algorithm basedon the season of entry. For example, the algorithm can be entered atstep 100 if pre-spring is the selected entry point. Otherwise, thealgorithm can be entered at step 110 if spring is the selected startingpoint, or at step 120 if summer is the selected entry point, or at step130 if fall is the selected entry point. Finally, the algorithm can beentered at step 140 if winter is the selected entry point. Although thealgorithm is described below using a pre-spring entry point, it will beunderstood that the algorithm operates identically no matter which entrypoint is selected. The user is responsible for selecting the entry pointinto the algorithm.

At step 102, the system determines whether the first inflection pointflag has been set. If this flag has been set, then the current date isbeyond the first inflection point in the solar cycle and the algorithmshould proceed to analyze whether the current date is beyond the secondinflection point. In other words, if the answer to step 102 isaffirmative, then control proceeds to step 112 and proceeds as describedbelow.

If the answer to step 102 is negative, then control proceeds to step 104where the system determines whether the first inflection point has beenreached. If the answer to this step is affirmative, then the point hasjust been reached and control proceeds to step 106 where the firstinflection point flag is set and control proceeds to step 108. Uponsubsequent entry into the algorithm, steps 104 through 108 will bebypassed.

If the answer at step 104 is negative, then the first inflection pointhas not been reached and control proceeds to step 108 where the lightingtime is set to the seasonal minimum value. After step 108 is executed,the algorithm is exited.

If the first inflection point flag has been set, indicating the currentdate (for which a lighting time is required) is not in the pre-springperiod, then the algorithm proceeds to step 112. At step 112, the systemdetermines whether the second inflection point flag has been setindicating the current date is not in the spring period. In other words,if the answer to step 112 is affirmative, then control proceeds to step122 and proceeds as described below.

If the answer to step 112 is negative, then control proceeds to step 114where the system determines whether the second inflection point has beenreached. If the answer to this step is affirmative, then the point hasjust been reached and control proceeds to step 116 where the secondinflection point flag is set. Then, control proceeds to step 118. Inthis case, upon the next entry into the algorithm, steps 114 through 118will be bypassed.

If the answer at step 114 is negative, then the second inflection pointhas not been reached and control proceeds to step 118 where the lightingtime is computed using a linear approximation. After step 118 has beenexecuted, the algorithm is exited. The linear approximation is made byadding a constant whose value depends upon the latitude of the locationwhere the system is based. For example, if the system were simulatingthe solar cycle in Miami, a value of 83 seconds would be adding to arunning total.

If the second inflection point flag has been set, indicating the currentdate (for which a lighting time is required) is not in the springperiod, then the algorithm proceeds to step 122. At step 122, the systemdetermines whether the third inflection point flag has been set whichindicates that the current date is not in the summer period. In otherwords, if the answer to step 122 is affirmative, then control proceedsto step 132 and proceeds as described below.

If the answer to step 122 is negative, then control proceeds to step 124where the system determines whether the third inflection point has beenreached. If the answer to this step is affirmative, then the point hasjust been reached and control proceeds to step 126 where the thirdinflection point flag is set and control proceeds to step 128. In thiscase, upon the next entry into the algorithm, steps 124 through 128 willbe bypassed.

If the answer at step 124 is negative, then the third inflection pointhas not been reached and control proceeds to step 128 where the lightingtime is set to the seasonal maximum value. After step 128 has beenexecuted, the algorithm is exited.

If the third inflection point flag has been set, indicating the currentdate (for which a lighting time is required) is not in the summerperiod, then the algorithm proceeds to step 132. At step 132, the systemdetermines whether the fourth inflection point flag has been set whichindicates that the current date is not in the fall period. In otherwords, if the answer to step 132 is affirmative, then control proceedsto step 142 and proceeds as described below.

If the answer to step 132 is negative, then control proceeds to step 134where the system determines whether the fourth inflection point has beenreached. If the answer to this step is affirmative, then the point hasjust been reached and control proceeds to step 136 where the fourthinflection point flag is set and control proceeds to step 138. In thiscase, upon the next entry into the algorithm, steps 134 through 138 willbe bypassed.

If the answer at step 134 is negative, then the fourth inflection pointhas not been reached and control proceeds to step 138 where the lightingtime is computed using linear approximations. The linear approximationis made by subtracting a constant whose value depends upon the latitudeof the location where the system is based. For example, if the systemwere simulating the solar cycle in Miami, a value of 83 seconds would besubtracted to a running total. After step 138, the algorithm is exited.

If the fourth inflection point flag has been set, indicating the currentdate (for which a lighting time is required) is not in the fall period,then the algorithm proceeds to step 142. At step 142, the systemdetermines whether the fifth inflection point flag has been set whichindicates that the current date is not in the fall period. In otherwords, if the answer to step 142 is affirmative, then control proceedsto step 112 and proceeds as described above.

If the answer to step 142 is negative, then control proceeds to step 144where the system determines whether the fifth inflection point has beenreached. If the answer to this step is affirmative, then the point hasjust been reached and control proceeds to step 146 where the fifthinflection point flag is set. Control then proceeds to step 148. In thiscase, upon the next entry into the algorithm, steps 144 through 148 willbe bypassed.

If the answer at step 144 is negative, then the fifth inflection pointhas not been reached and control proceeds to step 148 where the lightingtime is set to the seasonal minimum. After execution of step 148, thealgorithm is exited.

As can be seen from the above description, the algorithm requires theability to store the values of the inflection point flags upon exitingfrom the algorithm. Also, the algorithm is meant to be entered forcomputation of a lighting time on each day of the year.

Thus, an algorithm is provided that calculates the sinusoidal cyclerepresenting the amount of daily solar radiation by using the points inthe cycle of maximum and minimum inflection in the sinusoidal waveformin real time. Furthermore, the algorithm is adjustable for the properlatitude. The invention senses the dryness of the soil and is able toprovide the proper moisture level for the soil and other data concerningthe soil. The invention allows for the cycle to begin on the wintersolstice and proceeds with five sections creating the traditional fourseasons. The invention also provides a system that incorporates methodsof stimulating plant growth. Finally, the system is compact in size andeasy to use.

While the present invention has been described with reference to one ormore preferred embodiments, those skilled in the art will recognize thatmany changes may be made thereto without departing from the spirit andscope of the present invention which is set forth in the followingclaims.

We claim:
 1. A method for simulating the lighting cycle of the sun forplants in soil comprising the steps of:providing a plant in soil;calculating and identifying a set of four inflection points on a solarlighting cycle and obtaining the minimum daily number of minutes ofsunlight per year for a location at a predetermined latitude;reconstructing a piecewise-linear approximation of the daily and yearlysolar cycle based upon said set of inflection points and said minimumnumber of minutes; automatically determining the lighting period basedupon said daily and yearly cycles; and activating a lighting device forthe determined lighting period.
 2. The method of claim 1 containing thefurther step of activating a soil heater for a predetermined length oftime.
 3. The method of claim 1 containing the further step of applying aphysical stimulus to the soil.
 4. The method of claim 1 wherein saidsteps of obtaining a set of inflection points, reconstructing the dailyand yearly solar cycles, and determining the lighting periods areperformed by a microprocessor.
 5. The method of claim 1 wherein saidreconstructing begins on the winter solstice.
 6. The method of claim 1further including the step of adding fertilizer to the soil.
 7. Themethod of claim 1 further including the step of determining the pH ofthe soil.
 8. The method of claim 1 further including the step of heatingthe soil to a predetermined temperature.
 9. The method of claim 1further including the steps of monitoring the moisture level of the soiland maintaining said moisture level at a predetermined level.
 10. Amethod for simulating the lighting cycle of the sun for plants in soilcomprising the steps of:providing a plant in soil; calculating andidentifying a set of four inflection points on a solar lighting cycleand obtaining the minimum daily number of minutes of sunlight per yearfor a location at a predetermined latitude; reconstructing apiecewise-linear approximation of the daily and yearly solar cycle basedupon said set of inflection points and said minimum number of minutes,wherein said step of reconstructing the yearly solar cycle determinesfive piecewise linear sections representing the four seasons;automatically determining the lighting period based upon said daily andyearly cycles; and activating a lighting device for the determinedlighting period.
 11. The method of claim 10 wherein said reconstructingbegins on the winter solstice.
 12. The method of claim 10 furtherincluding the step of adding fertilizer to the soil.
 13. The method ofclaim 10 further including the step of determining the pH of the soil.14. The method of claim 10 further including the step of heating thesoil to a predetermined temperature.
 15. The method of claim 10 furtherincluding the steps of monitoring the moisture level of the soil andmaintaining said moisture level at a predetermined level.
 16. A methodfor simulating the lighting cycle of the sun comprising the stepsof:calculating and identifying a set of four inflection points on asolar lighting cycle and obtaining the minimum daily number of minutesof sunlight per year for a location at a predetermined latitude;reconstructing a piecewise-linear approximation of the daily and yearlysolar cycle based upon said set of inflection points and said minimumnumber of minutes; automatically determining the lighting period basedupon said daily and yearly cycles; and activating a lighting device forthe determined lighting period; monitoring the moisture level of thesoil and maintaining said moisture level at a predetermined level; andheating the soil to a predetermined temperature.
 17. A method forsimulating the lighting cycle of the sun for plants in soil comprisingthe steps of:providing a plant in soil; calculating and identifying aset of four inflection points on a solar lighting cycle and obtainingthe minimum daily number of minutes of sunlight per year for a locationat a predetermined latitude; reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based upon said set ofinflection points and said minimum number of minutes; automaticallydetermining the lighting period based upon said daily and yearly cycles;and activating a lighting device for the determined lighting period;monitoring the moisture level of the soil and maintaining said moisturelevel at a predetermined level; heating the soil to a predeterminedtemperature; determining the pH of the soil; adding fertilizer to thesoil; and applying a physical stimulus to the soil.
 18. An electronicsystem for simulating the lighting cycle of the sun for plants in soilcomprising:means for calculating and identifying a set of fourinflection points on a solar lighting cycle and obtaining the minimumdaily number of minutes of sunlight per year for a location at apredetermined latitude; means for reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based about said setof inflection points and said minimum number of minutes; means forautomatically determining the lighting period based upon said daily andyearly cycles; means for activating a lighting device for the determinedlighting period; and means for applying a physical stimulus to the soil.19. An electronic system for simulating the lighting cycle of the sunfor plants in soil comprising:means for calculating and identifying aset of four inflection points on a solar lighting cycle and obtainingthe minimum daily number of minutes of sunlight per year for a locationat a predetermined latitude; means for reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based about said setof inflection points and said minimum number of minutes; means forautomatically determining the lighting period based upon said daily andyearly cycles; means for activating a lighting device for the determinedlighting period; and means for dispensing fertilizer to said plants. 20.An electronic system for simulating the lighting cycle of the sun forplants in soil comprising:means for calculating and identifying a set offour inflection points on a solar lighting cycle and obtaining theminimum daily number of minutes of sunlight per year for a location at apredetermined latitude; means for reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based about said setof inflection points and said minimum number of minutes; means forautomatically determining the lighting period based upon said daily andyearly cycles; means for activating a lighting device for the determinedlighting period; and means for determining the pH of the soil.
 21. Anelectronic system for simulating the lighting cycle of the sun forplants in soil comprising:means for calculating and identifying a set offour inflection points on a solar lighting cycle and obtaining theminimum daily number of minutes of sunlight per year for a location at apredetermined latitude; means for reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based about said setof inflection points and said minimum number of minutes; means forautomatically determining the lighting period based upon said daily andyearly cycles; means for activating a lighting device for the determinedlighting period; and means for determining the moisture level of thesoil and means for maintaining the moisture level at a predeterminedlevel.
 22. A network comprising:a multitude of remote units, said unitsinterconnected and communicatively coupled to each other units, eachremote unit for simulating the cycle of the sun for plants in soil, saidremote units comprising means for calculating and identifying a set ofinflection points on a solar lighting cycle and obtaining the minimumdaily number of minutes of sunlight per year for a location at apredetermined latitude; means for reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based about said setof inflection point and said minimum number of minutes; means fordetermining the lighting period based upon said daily and yearly cycles;a lighting device; a controller for sensing environmental conditions; acontrol panel coupled to said control panel for accepting commands froma user and displaying information to a user; and means for activatingsaid lighting device for the determined lighting period; and centralcontroller means coupled to said remote units for monitoring theperformance of said remote units, wherein said remote units furthercomprise means for applying a physical stimulus to the soil.
 23. Anetwork comprising:a multitude of remote units, said unitsinterconnected and communicatively coupled to each other units, eachremote unit for simulating the cycle of the sun for plants in soil, saidremote units comprising means for calculating and identifying a set ofinflection points on a solar lighting cycle and obtaining the minimumdaily number of minutes of sunlight per year for a location at apredetermined latitude; means for reconstructing a piecewise-linearapproximation of the daily and yearly solar cycle based about said setof inflection point and said minimum number of minutes; means fordetermining the lighting period based upon said daily and yearly cycles;a lighting device; a controller for sensing environmental conditions; acontrol panel coupled to said control panel for accepting commands froma user and displaying information to a user; and means for activatingsaid lighting device for the determined lighting period; and centralcontroller means coupled to said remote units for monitoring theperformance of said remote units, wherein said remote units furthercomprise means for dispensing fertilizer to said plants.
 24. A networkcomprising:a multitude of remote units, said units interconnected andcommunicatively coupled to each other units, each remote unit forsimulating the cycle of the sun for plants in soil, said remote unitscomprising means for calculating and identifying a set of inflectionpoints on a solar lighting cycle and obtaining the minimum daily numberof minutes of sunlight per year for a location at a predeterminedlatitude; means for reconstructing a piecewise-linear approximation ofthe daily and yearly solar cycle based about said set of inflectionpoint and said minimum number of minutes; means for determining thelighting period based upon said daily and yearly cycles; a lightingdevice; a controller for sensing environmental conditions; a controlpanel coupled to said control panel for accepting commands from a userand displaying information to a user; and means for activating saidlighting device for the determined lighting period; and centralcontroller means coupled to said remote units for monitoring theperformance of said remote units, wherein said remote units furthercomprise means for determining the pH of the soil.
 25. An electronicsystem for simulating the lighting cycle of the sun comprising:means forcalculating and identifying a set of four inflection points on a solarlighting cycle and obtaining the minimum daily number of minutes ofsunlight per year for a location at a predetermined latitude; means forreconstructing a piecewise-linear approximation of the daily and yearlysolar cycle based about said set of inflection points and said minimumnumber of minutes; means for automatically determining the lightingperiod based upon said daily and yearly cycles; a lighting device; acontroller for sensing environmental conditions; a control panel coupledto said controller for accepting commands from a user and displayinginformation to a user; and means for activating said lighting device forthe determined lighting period.
 26. An electronic system for simulatingthe lighting cycle of the sun for plants in soil comprising:means forcalculating and identifying a set of four inflection points on a solarlighting cycle and calculating the minimum daily number of minutes ofsunlight per year for a location at a predetermined latitude; means forreconstructing the daily and yearly solar cycle based about said set ofinflection points and said minimum number of minutes, saidreconstruction determining five piecewise linear sections representingthe four seasons; means for automatically calculating the lightingperiod based upon said daily and yearly cycles; means for determiningthe pH of the soil; and means for activating a lighting device for thedetermined lighting period.